Transmission electron microscope studies of the quadriflagellate
zoospores of the parasitic, subaerial green alga Cephaleuros virescens Kunze
have provided a basis for comparison between these motile cells and
biflagellate gametes previously examined.1 As seen in
cross-section (Fig. 1), the four basal bodies form a trapezoid in which the
two upper basal bodies are closer together than the two lower basal bodies.
The basal bodies are parallel, overlapping, and interdigitated. Two flagella
are inserted into either side of the apical papilla and terminate in
diagonally opposed basal bodies. The bilaterally keeled flagella (Fig. 2)
are often closely appressed thereby creating a biflagellate appearance. Each
of the four basal bodies is associated with a microtubular spline which
extends posteriorly beneath the plasmalemma. A densely stained flagellar cap
is present at the end of each basal body and together with the terminal
region of its spline, forms a multilayered structure (MLS). Although the
MLSs associated with the two lower basal bodies (Fig. 3) are virtually
identical to those found in the gametes, those associated with the upper
basal bodies are morphologically different or positioned in such a manner
that “typical” sectional views cannot be obtained. The observations reveal
that although minor differences exist, the zoospores of Cephaleuros are
similar to those of Phycopeltis,2 a related
genus.
Rapid Cross-Section TEM Specimen Preparation of III-V Materials
